Chemical coagulation-biological

Treatment of dye wastewater involves physical, physico-chemical, chemical, and biological methods. Physical processes are dilution, filtration, and gamma radiation. Physico-chemical includes adsorption, coagulation, flocculation, precipitation, reverse osmosis, ion exchange, etc. 

Chemical coagulation — flocculation sedimentation Coalescers Membrane processes Biological processes Carbon adsorption Inorganics Organics... 

Solvents, extender oils, and insoluble monomers are used throughout the rubber industry. In addition, miscellaneous oils are used to lubricate machinery. Laboratory analysis indicates the presence of oil and grease in the raw wastewater of these plants. Oil and grease entering the wastewater streams are removed by chemical coagulation, dissolved air flotation, and, to some extent, biological oxidation. 

Dave et al. (1985) reported the biodegradation of toxic cyanide waste. The effluent was pretreated with hot alkah digestion and chemical coagulation followed by biological aeration. The HCN content in black gram and other seeds at a level of 1 mg/100 g flour was completely destroyed in 20-minute cooking (Dwivedi and Singh 1987). 

The physical removal of combined chemical coagulation and physical removal of solids from wastewater is classified as primary treatment, especially if these processes are followed by biological treatment. pH adjustment is frequently used to convert soluble contaminants such as heavy metals to particulate matter, which can then be removed. 

Points of Chemical Addition In independent physical-chemical treatment or in phosphate removal in the primary clarifier ahead of biological treatment, chemicals are added to raw sewage. In tertiary treatment for phosphate removal and suspended solids (SS) reduction, they are added to secondary effluent. In both cases, proper mixing and flocculation units are needed. For phosphate removal or improvement of SS capmre in biological secondary treatment, chemicals are often added directly to aeration units or prior to secondary settling units, without separate mixing and flocculation. In some phosphate removal applications coagulants are added at... 

End-of-pipe treatment refers to the application of chemical, biological, and physical processes to reduce the toxicity or volume of downstream waste. Treatment options include biological systems, chemical precipitation, flocculation, coagulation, and incineration as well as boilers and industrial furnaces (BIFs). 

Results of model simulations of effects of coagulation (a = 0.1) and sedimentation at steady state in Lake Zurich during summer are presented in Fig. 7.16. Particle volume concentrations in the epilimnion and hypolimnion are plotted as functions of the particle production flux in the epilimnion. Biological degradation and chemical dissolution of particles are neglected in these calculations. Predicted particle... 

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